package com.zihao;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.SecureRandom;
 
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
 
/**
 * <p>
 * AES加密解密工具包
 * </p>
 *
 * @author IceWee
 * @date 2012-5-18
 * @version 1.0
 */
public class AESUtils {
 
    private static final String ALGORITHM = "AES";
    private static final int KEY_SIZE = 128;
    private static final int CACHE_SIZE = 1024;
     
    /**
     * <p>
     * 生成随机密钥
     * </p>
     *
     * @return
     * @throws Exception
     */
    public static String getSecretKey() throws Exception {
        return getSecretKey(null);
    }
     
    /**
     * <p>
     * 生成密钥
     * </p>
     *
     * @param seed 密钥种子
     * @return
     * @throws Exception
     */
    public static String getSecretKey(String seed) throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
        SecureRandom secureRandom;
        if (seed != null && !"".equals(seed)) {
            secureRandom = new SecureRandom(seed.getBytes());
        } else {
            secureRandom = new SecureRandom();
        }
        keyGenerator.init(KEY_SIZE, secureRandom);
        SecretKey secretKey = keyGenerator.generateKey();
        return Base64Utils.encode(secretKey.getEncoded());
    }
     
    /**
     * <p>
     * 加密
     * </p>
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encrypt(byte[] data, String key) throws Exception {
        Key k = toKey(Base64Utils.decode(key));
        byte[] raw = k.getEncoded();
        SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
        return cipher.doFinal(data);
    }
     
    /**
     * <p>
     * 文件加密
     * </p>
     *
     * @param key
     * @param sourceFilePath
     * @param destFilePath
     * @throws Exception
     */
    public static void encryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
        File sourceFile = new File(sourceFilePath);
        File destFile = new File(destFilePath);
        if (sourceFile.exists() && sourceFile.isFile()) {
            if (!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            InputStream in = new FileInputStream(sourceFile);
            OutputStream out = new FileOutputStream(destFile);
            Key k = toKey(Base64Utils.decode(key));
            byte[] raw = k.getEncoded();
            SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
            Cipher cipher = Cipher.getInstance(ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
            CipherInputStream cin = new CipherInputStream(in, cipher);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = cin.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            cin.close();
            in.close();
        }
        else{
        	
        }
    }
     
  public static byte[] decrypt(byte[] data, String key) throws Exception {
    Key k = toKey(Base64Utils.decode(key));
    byte[] raw = k.getEncoded();
    SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
    Cipher cipher = Cipher.getInstance(ALGORITHM);
    cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
    return cipher.doFinal(data);
   }

  /**
   * <p>
   * 文件解密
   * </p>
   *
   * @param key
   * @param sourceFilePath
   * @param destFilePath
   * @throws Exception
   */
  public static void decryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
    File sourceFile = new File(sourceFilePath);
    File destFile = new File(destFilePath);
    if (sourceFile.exists() && sourceFile.isFile()) {
      if (!destFile.getParentFile().exists()) {
        destFile.getParentFile().mkdirs();
       }
      destFile.createNewFile();
      FileInputStream in = new FileInputStream(sourceFile);
      FileOutputStream out = new FileOutputStream(destFile);
      Key k = toKey(Base64Utils.decode(key));
      byte[] raw = k.getEncoded();
      SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
      Cipher cipher = Cipher.getInstance(ALGORITHM);
      cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
      CipherOutputStream cout = new CipherOutputStream(out, cipher);
      byte[] cache = new byte[CACHE_SIZE];
      int nRead = 0;
      while ((nRead = in.read(cache)) != -1) {
        cout.write(cache, 0, nRead);
        cout.flush();
       }
      cout.close();
      out.close();
      in.close();
     }
   }
    private static Key toKey(byte[] key) throws Exception {
        SecretKey secretKey = new SecretKeySpec(key, ALGORITHM);
        return secretKey;
    }
     
}

